Manufacture of felt



Patented May 2, 1939 v UNITED STATES MANUFACTURE OF FELT I Johannes Kleine, Dessau, and Walter Brennecke, Donnagen, Germany, assignors to I. G. Farbenindustrie Aktiengesellschaft, Frankfort-onthe-Main, Germany No Drawing. Application May 23, 1936, Serial No. 81,540. In Germany May 25, 1935 1 Claim.

Our present invention relates to the manufacture of felt.

It is known to produce a felt in which part of the animal fibers has been substituted by artificial fibers of cellulose hydrate. However, it has been found that an addition of artificial fibers of cellulose hydrate such as are obtained according to the copper oxide ammonia or the viscose process is only possible in certain cases because these fibers do not stand the carbonization usual in the manufacture of wool felt.

It is therefore an object of the present invention to provide an improved felt consisting of a mixture of wool and thermoplastic artificial fibers, which will withstand carbonization.

A further object of the invention consists in the provision of a felt which has improved mechanical properties in comparison with a felt consisting of a mixture of wool and cellulose hydrate fibers.

Further objects will become apparent from the following detailed specification.

According to this invention a felt of good quality which is capable of carbonization may be produced from a mixture of animal fibers such as wool or hairs, with artificial fibers from organic polymerization products. Fibers made from polymerization products of an unsaturated organic compound, such as polyvinyl esters, for example polyvinyl chloride, polyvinyl acetate, after-chlorinated polyvinyl chloride, polyacrylic acid esters, mixed polymerizates of the above bodies, or lower polyvinyl ethers such as polyvinylisobutylether, polypropylvinylether, chlorocautchouc, mixtures of these ethers or of the ethers with the esters, or mixtures of the polyvinyl compounds with diene compounds, such as butadiene, methylbutadiene, dimethylbutadiene, chloropropene are especially valuable for this purpose. For making felt it is particularly advantageous that these bodies have a comparatively low softening point, so that they acquire a certain amount of stickiness at the temperature usual in the manufacture of felt, thus imparting an internal strength to the 45 fibrous felt, which could not be obtained with fibers consisting of cellulose.

The proportion 61' artificial fiber in the mixture may be selected as desired. Very useful mixtures are those containing from 15 to 25 per cent of artificial fibers from an organic polymerization product. However, the admixture of artificial fibers may be raised to 30 or even 50 per cent. It is also possible to use a mixture of artificial fiber from an organic polymerization product and rayon staple fibers. In this case the admixture of artificial fibers should not surpass 50 per cent. In the mixture of artificial fibers there are preferred equal parts of cellulose hydrate fibers and artificial fibers from an organic polymerization product. but the amount of artificial fibers from an organic polymerization product should not be less than 10 per cent. If fibers of cellulose hydrate are present in the mixture, the wool should be carbonized before manufacturing the felt, if carbonization of the wool is necessary.

It could not be foreseen that artificial fibers made from organic polymers of high molecular weight would withstand the usual steps in the process of felting and fulling and would yield a useful mixture with wool. The resinous fibers have the property of shrinking more strongly than wool in the felting and fulling processes. In

fany cases this is an advantage.

The dyeing properties of the artificial fibers in question differ from those of wool. If uniform dyeing of the felt made from the mixed fibers is desired, it is preferable to dye both kinds of fibers, or at least one of them, beforemaking the mixture. The difference in the dyeing capacity existing between wool and the resin fibers may be made use of for the production of mottled felt. Spinning artificial fibers together with white wool and subsequently top-dyeing with wool dyestuffs produces an uniformly mottled felt of excellent quality.

The following examples illustrate the invention:

Example 1.--3200 grams of a mixture of equal parts of wool waste and South African wool and 800 grams of artificial fibers from after-chlorinated polyvinyl chloride are mixed and carded in the usual manner, again mixed and oiled. After thorough working, the mixture is passed into a carding machine and wound in the usual manner on a lap drum. The lap formed on the drum is cut and subdivided into equal portions of 350 to 400 grams. The weighed quantities are fed at right angles to the direction of the fibers to a carding cone. The double cone thus produced is out along the base of the cone and felted on a plate felting machine. After it has been fulled in dilute sulfuric acid the felt is carbonized in the usual manner and passed to the fulling beaters, and the wool dyed in the usual manner. In general, the polyvinyl chloride fibers remain undyed in this operation. The finishing operations are those usual in the hat-making industry.

Example 2.-80 per cent of wool are thoroughly mixed by carding them s everal times with 10 per cent of rayon staple fibers and 10 per cent of fibers from polyvinyl chloride, and carded to slivers on a wool carding machine, which when worked up on a plate felting machine yield a felt which has the same properties as a felt from pure wool.

Example 3.70 parts of wool, 15 parts of rayon staple fibers and 15 parts of artificial fibers from polyvinylchloride are mixed by carding and the mixture is worked up as described in the preceding example.

Example 4.'70 parts of wool are mixed with 20 parts of rayon staple fibers and 10 parts of artificial fibers from polyvinyl chloride and worked up to a felt in form of plates in the usual manner.

What we claim is:

A soft pliable felt, resembling a felt consisting entirely of wool, but having a different affinity for acid wool dyestufis and a substantially improved internal strength compared with a felt comprising wool and cellulose hydrate fibers, said felt consisting of a mixture of wool and at most the same quantity of thermoplastic fibers from a polymerization product of organic unsaturated compounds selected from the group consisting of polyvinylesters, polyvinylethers and mixtures of these compounds, chlorinated rubber, and polymerization products of mixtures of vinyl compounds with dienes.

JOHANNES KLEINE.

I WALTER BRENNECKE. 

